Using a speaker/personal speakerphone or earplug (not wireless) during conversation - distancing the mobile phone from the user’s body reduces his exposure to the radiowave radiation. Therefore, keep the mobile phone at a distance from the body (do not carry it on the body, such as in the belt, pocket or on a neck strap). Obviously, reducing the amount and duration of calls on the mobile phone is another simple measure to reduce exposure.
I really want to caution you to be careful of any "expert" or EMF blogger recommending anti-radiation filtering cases, stickers that attach to the phone or necklaces to "ward off" EMF.  I get it, when I first realized 25 years ago that I was sensitive to electromagnetic energy and then later, when I understood that without a doubt, man made electromagnetic radiation has a biological effect on my body, I wanted an easy fix.  I tried the shielding materials and cases and I just did not feel any better.  Then I bought meters to see if the energy changed and I actually noticed what the California Department of Health now says and it's what the FTC and FCC post warnings about:  "Some shielding materials can make exposures worse". So please, be careful and read on for what you can do to avoid electromagnetic radiation exposure.
In order to protect the population living around base stations and users of mobile handsets, governments and regulatory bodies adopt safety standards, which translate to limits on exposure levels below a certain value. There are many proposed national and international standards, but that of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) is the most respected one, and has been adopted so far by more than 80 countries. For radio stations, ICNIRP proposes two safety levels: one for occupational exposure, another one for the general population. Currently there are efforts underway to harmonise the different standards in existence.[26]
The pacemaker studies were a harbinger of bad things to come. Results showed that cell phones do indeed interfere with pacemakers, but moving the phone away from the pacemaker would correct the problem. Amazingly, the industry was extremely upset with the report, complaining that the researchers went off target. When Dr. Carlo and his colleagues published their findings in the New England Journal of Medicine in 1997,11 the industry promptly cut off funding for the overall program. It took nine months for the FDA and the industry to agree on a scaled-down version of the program to continue going forward. Dr. Carlo had volunteered to step down, since he was clearly not seeing eye-to-eye with the industry, but his contract was extended instead, as no one wanted to look bad from a public relations standpoint.
Most of the research is attributed to "SPSU," which is presumably St. Petersburg State Polytechnic University, and some of the research, it is suggested, was conducted at the Kirov Military Medical Academy, though it's unclear why a military academy would conduct clinical research on civilian cell phone radiation. The names of the scientists who conducted these studies are conspicuously absent, as are any published results.
The bulk of scientific evidence says that cellphone radiation doesn’t harm humans, according to the Food and Drug Administration: our cellphones are much more likely to kill us when we glance down at them while driving. But people are bad at judging risk. And the word “radiation” combined with the fact that we can’t see or control the invisible forces emanating from our cellphones becomes a perfect recipe for fear.
And even with these unusually high levels of exposure, the links to cancer were still “mostly equivocal, or ambiguous,” according to the FDA’s statement. In fact, the rats exposed to cell phone radiation actually appeared to live longer than the ones that weren’t, a finding that the FDA’s Shuren says the agency is assessing. The difference could simply be the result of chance, STAT News reports.
A series of studies testing different scenarios (called simulations by the study authors) were carried out using incidence data from the Nordic countries to determine the likelihood of detecting various levels of risk as reported in studies of cell phone use and brain tumors between 1979 and 2008. The results were compatible with no increased risks from cell phones, as reported by most epidemiologic studies. The findings did suggest that the increase reported among the subset of heaviest regular users in the Interphone study could not be ruled out but was unlikely. The highly increased risks reported in the Swedish pooled analysis were strongly inconsistent with the observed glioma rates in the Nordic countries (24).

Cell phone radiation emissions present the greatest potential health risks when directly touching the body, especially the head, breasts and reproductive organs. This is referred to as zero distance to the body. Moving your cell phone away from your body just a few inches reduces the health risks. As a rule of thumb, when a cell phone is moved at least one foot away from the head or body, cell phone radiation is reduced by as much as 80%.
None of the three cases contain metallic parts, which are known to affect SAR, but all increased the user’s radiation exposure. The effect on radiation exposure would likely vary with each of the hundreds of cases on the market, and each would have to be tested individually to come up with an exact measure. The results in Table 1, however, are believed to reflect the range of radiation increases.
If you want to measure the EMF radiation from your own phone, and know if EMF protection products are working, you should get a quality EMF meter. I highly recommend the new TriField TF2 (read my review) as it’s simple to use, lasts forever, is extremely accurate, and measures all three types of EMF radiation. If you’re looking for a low-cost EMF meter I really like the Meterk (read my review).
Consumers should utilize an air tube headset as a safer alternative to wired headsets or in-ear Bluetooth headsets, use the speaker feature and keep phones away from your body unless there is RF radiation shielding between the wireless device and cell phone users body.  When carrying a phone on your body it’s highly recommended to use either an RF Safe flip cover radiation shielded phone case or pocket shield to deflect excessive radiation away.
In conclusion: It is still unclear whether use of cellular technology is associated with an increased risk to develop malignant and benign tumors, but taking into account the results of recent studies, the Ministry of Health adopts the precautionary principle and follows the recommendations listed in the “Ministry of Health Recommendations” (below).
That’s because of a new anti-radiation phone case from SafeSleeve, a small company that started making anti-radiation laptop cases roughly three years ago. "I was using my laptop computer on my lap, and a friend of mine told me I shouldn’t,” says company co-founder Cary Subel. “His dad was a urologist, who had told him that the effects of the radiation and heat can affect your fertility and potentially cause all sorts of other issues. So it was in the back of my mind. When I went to college, I was always using my laptop on my lap more and more, but I was hesitant. I figured there was something out there to block the radiation and heat. But I looked it up and there wasn’t much.” He says he developed a case for the laptop that did the job. From there, the cell phone cases became a natural progression, and through a 2014 Kickstarter campaign became reality.
One of the many advantages of TI22 is that after applying TI22 to your device it will have an invisible layer that will protect your device from harmful EMF radiation scratches and scuffs for up to one year. This layer reaches the full hardness of 9H on the Mohs scale of mineral hardness, which is a scale that characterizes scratch resistance, and is similar to Sapphire, Ruby or Corundum. Its almost as hard as a Diamond.
In one type of study, called a case–control study, cell phone use is compared between people with these types of tumors and people without them. In another type of study, called a cohort study, a large group of people who do not have cancer at study entry is followed over time and the rate of these tumors in people who did and didn’t use cell phones is compared. Cancer incidence data can also be analyzed over time to see if the rates of brain tumors changed in large populations during the time that cell phone use increased dramatically. These studies have not shown clear evidence of a relationship between cell phone use and cancer. However, researchers have reported some statistically significant associations for certain subgroups of people.